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<?php/*** TMemCache class file** @author Qiang Xue <qiang.xue@gmail.com>* @author Carl G. Mathisen <carlgmathisen@gmail.com>* @link http://www.pradosoft.com/* @copyright Copyright © 2005-2008 PradoSoft* @license http://www.pradosoft.com/license/* @version $Id: TMemCache.php 2541 2008-10-21 15:05:13Z qiang.xue $* @package System.Caching*//*** TMemCache class** TMemCache implements a cache application module based on {@link http://www.danga.com/memcached/ memcached}.** TMemCache can be configured with the Host and Port properties, which* specify the host and port of the memcache server to be used.* By default, they take the value 'localhost' and 11211, respectively.* These properties must be set before {@link init} is invoked.** The following basic cache operations are implemented:* - {@link get} : retrieve the value with a key (if any) from cache* - {@link set} : store the value with a key into cache* - {@link add} : store the value only if cache does not have this key* - {@link delete} : delete the value with the specified key from cache* - {@link flush} : delete all values from cache** Each value is associated with an expiration time. The {@link get} operation* ensures that any expired value will not be returned. The expiration time can* be specified by the number of seconds (maximum 60*60*24*30)* or a UNIX timestamp. A expiration time 0 represents never expire.** By definition, cache does not ensure the existence of a value* even if it never expires. Cache is not meant to be an persistent storage.** Also note, there is no security measure to protected data in memcache.* All data in memcache can be accessed by any process running in the system.** To use this module, the memcache PHP extension must be loaded.** Some usage examples of TMemCache are as follows,* <code>* $cache=new TMemCache; // TMemCache may also be loaded as a Prado application module* $cache->init(null);* $cache->add('object',$object);* $object2=$cache->get('object');* </code>** You can configure TMemCache two different ways. If you only need one memcache server* you may use the method as follows.* <code>* <module id="cache" class="System.Caching.TMemCache" Host="localhost" Port="11211" />* </code>** If you want a more complex configuration, you may use the method as follows.* <code>* <module id="cache" classs="System.Caching.TMemCache">* <server Host="localhost" Port="11211" Weight="1" Timeout="300" RetryInterval="15" />* <server Host="anotherhost" Port="11211" Weight="1" Timeout="300" RetryInterval="15" />* </module>* </code>** If loaded, TMemCache will register itself with {@link TApplication} as the* cache module. It can be accessed via {@link TApplication::getCache()}.** TMemCache may be configured in application configuration file as follows* <code>* <module id="cache" class="System.Caching.TMemCache" Host="localhost" Port="11211" />* </code>* where {@link getHost Host} and {@link getPort Port} are configurable properties* of TMemCache.** @author Qiang Xue <qiang.xue@gmail.com>* @version $Id: TMemCache.php 2541 2008-10-21 15:05:13Z qiang.xue $* @package System.Caching* @since 3.0*/class TMemCache extends TCache{/*** @var boolean if the module is initialized*/private $_initialized=false;/*** @var Memcache the Memcache instance*/private $_cache=null;/*** @var string a unique prefix used to identify this cache instance from the others*/private $_prefix=null;/*** @var string host name of the memcache server*/private $_host='localhost';/*** @var integer the port number of the memcache server*/private $_port=11211;/*** @var boolean controls the use of a persistent connection. Default to true.*/private $_persistence = true;/*** @var integer number of buckets to create for this server which in turn control its* probability of it being selected. The probability is relative to the total weight* of all servers.*/private $_weight = 1;private $_timeout = 360;private $_retryInterval = 15;private $_status = true;private $_failureCallback = null;/*** @var array list of servers available*/private $_servers=array();/*** Destructor.* Disconnect the memcache server.*/public function __destruct(){if($this->_cache!==null)$this->_cache->close();}/*** Initializes this module.* This method is required by the IModule interface. It makes sure that* UniquePrefix has been set, creates a Memcache instance and connects* to the memcache server.* @param TApplication Prado application, can be null* @param TXmlElement configuration for this module, can be null* @throws TConfigurationException if memcache extension is not installed or memcache sever connection fails*/public function init($config){if(!extension_loaded('memcache'))throw new TConfigurationException('memcache_extension_required');$this->_cache=new Memcache;$this->loadConfig($config);if(count($this->_servers)){foreach($this->_servers as $server){Prado::trace('Adding server '.$server['Host'].' from serverlist', 'System.Caching.TMemCache');if($this->_cache->addServer($server['Host'],$server['Port'],$server['Persistent'],$server['Weight'],$server['Timeout'],$server['RetryInterval'])===false)throw new TConfigurationException('memcache_connection_failed',$server['Host'],$server['Port']);}}else{Prado::trace('Adding server '.$this->_host, 'System.Caching.TMemCache');if($this->_cache->addServer($this->_host,$this->_port)===false)throw new TConfigurationException('memcache_connection_failed',$this->_host,$this->_port);}$this->_initialized=true;parent::init($config);}/*** Loads configuration from an XML element* @param TXmlElement configuration node* @throws TConfigurationException if log route class or type is not specified*/private function loadConfig($xml){if($xml instanceof TXmlElement){foreach($xml->getElementsByTagName('server') as $serverConfig){$properties=$serverConfig->getAttributes();if(($host=$properties->remove('Host'))===null)throw new TConfigurationException('memcache_serverhost_required');if(($port=$properties->remove('Port'))===null)throw new TConfigurationException('memcache_serverport_required');if(!is_numeric($port))throw new TConfigurationException('memcache_serverport_invalid');$server = array('Host'=>$host,'Port'=>$port,'Weight'=>1,'Timeout'=>1800,'RetryInterval'=>15,'Persistent'=>true);$checks = array('Weight'=>'memcache_serverweight_invalid','Timeout'=>'memcache_servertimeout_invalid','RetryInterval'=>'memcach_serverretryinterval_invalid');foreach($checks as $property=>$exception){$value=$properties->remove($property);if($value!==null && is_numeric($value))$server[$property]=$value;else if($value!==null)throw new TConfigurationException($exception);}$server['Persistent']= TPropertyValue::ensureBoolean($properties->remove('Persistent'));$this->_servers[]=$server;}}}/*** @return string host name of the memcache server*/public function getHost(){return $this->_host;}/*** @param string host name of the memcache server* @throws TInvalidOperationException if the module is already initialized*/public function setHost($value){if($this->_initialized)throw new TInvalidOperationException('memcache_host_unchangeable');else$this->_host=$value;}/*** @return integer port number of the memcache server*/public function getPort(){return $this->_port;}/*** @param integer port number of the memcache server* @throws TInvalidOperationException if the module is already initialized*/public function setPort($value){if($this->_initialized)throw new TInvalidOperationException('memcache_port_unchangeable');else$this->_port=TPropertyValue::ensureInteger($value);}/*** Retrieves a value from cache with a specified key.* This is the implementation of the method declared in the parent class.* @param string a unique key identifying the cached value* @return string the value stored in cache, false if the value is not in the cache or expired.*/protected function getValue($key){return $this->_cache->get($key);}/*** Stores a value identified by a key in cache.* This is the implementation of the method declared in the parent class.** @param string the key identifying the value to be cached* @param string the value to be cached* @param integer the number of seconds in which the cached value will expire. 0 means never expire.* @return boolean true if the value is successfully stored into cache, false otherwise*/protected function setValue($key,$value,$expire){return $this->_cache->set($key,$value,0,$expire);}/*** Stores a value identified by a key into cache if the cache does not contain this key.* This is the implementation of the method declared in the parent class.** @param string the key identifying the value to be cached* @param string the value to be cached* @param integer the number of seconds in which the cached value will expire. 0 means never expire.* @return boolean true if the value is successfully stored into cache, false otherwise*/protected function addValue($key,$value,$expire){return $this->_cache->add($key,$value,0,$expire);}/*** Deletes a value with the specified key from cache* This is the implementation of the method declared in the parent class.* @param string the key of the value to be deleted* @return boolean if no error happens during deletion*/protected function deleteValue($key){return $this->_cache->delete($key);}/*** Deletes all values from cache.* Be careful of performing this operation if the cache is shared by multiple applications.*/public function flush(){return $this->_cache->flush();}}